Jose Ronald Santo-Alvarez (Hudson County Prosecutor's Office)

The suspect in the murder of his ex-girlfriend from Jersey City and their 4-year-old son was shot by police as he was being taken into custody on Thursday night.

Bergen County Prosecutor John Molinelli said that Jose Santos-Alvarez was shot as he hid in the back of a house on Clay Street in Hackensack. Molinelli said as several officers attempted to apprehended the 25-year-old, he showed a knife in a small kitchen area and was shot once in the abdomen.

Molinelli said that Santos-Alvarez underwent surgery for the wound, which is believed to be non-life-threatening.

Santos-Alvarez was wanted on two counts of first degree murder in the deaths of his estranged girlfriend and their young son. Twenty-seven-year-old Monika Potoczniak and 4-year-old Christopher Potoczniak were found unconscious Oct. 7 in their Jersey City apartment. They were taken to a hospital, where they were pronounced dead. Authorities say Monika Potoczniak had been strangled and her son had been suffocated.